The development of computers into hand-held and mobile devices has led to a situation where these devices are used in many different environments and situations, that is, in different contexts. In addition, there are a large number of applications available for these devices, each using the device's resources differently. Also users have different needs and preferences how they operate such devices. At the same time, the demands on energy efficiency and time of use are increasing.
There are known energy management systems that may e.g. put some elements of a device in a low-power mode when these elements are not needed. The well-known screen saver feature is an example of such a system: when there is no user activity, the screen is dimmed or blanked completely. Some computer systems spin down the hard disk when there has been no data access for a while. Thus, the operation of the device may be adapted to the user's needs according to the current context.
However, there is a vast number of different contexts that may be relevant to the task of energy management. Furthermore, it may sometimes be difficult to carry out energy management even though the context is known—it may not be known, which elements are needed or are not needed in such a context.
There is, therefore, a need for a solution that makes it easier and more efficient to carry out energy management.